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if we fallowed https://sourceware.org/glibc/wiki/Y2038ProofnessDesign for Y2038 fix(where all timer related variable moved to 64 bit instead of 32 bit ), pthread_cond_timedwait function from gthr_posix.h is calling different function in pthrea_cond_wait.c of glibc(due to weakref of symbol pthread_cond_timedwait())  which impacting the time value.

From pthread.h
extern int pthread_cond_timedwait (pthread_cond_t *__restrict __cond, pthread_mutex_t *__restrict __mutex, const struct timespec *__restrict __abstime) __asm__ ("" "__pthread_cond_timedwait64")

From gthread_posix.h:
static __typeof(pthread_cond_timedwait) __gthrw_pthread_cond_timedwait __attribute__ ((__weakref__("pthread_cond_timedwait"), __copy__ (pthread_cond_timedwait)));


__gthrw_(pthread_cond_timedwait) --> ___pthread_cond_timedwait   invoking in glibc instead of   __pthread_cond_timedwait64 which is impacting time value as __pthread_cond_timedwait is converting value from 32 bit to 64 bit.

normal pthread_cond_timedwait is invoking __pthread_cond_timedwait64 properly and its working fine.

From: pthread_cond_wait.c

#if __TIMESIZE == 64
strong_alias (___pthread_cond_timedwait64, ___pthread_cond_timedwait)
#else
strong_alias (___pthread_cond_timedwait64, __pthread_cond_timedwait64)
libc_hidden_def (__pthread_cond_timedwait64)

int
___pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
                            const struct timespec *abstime)
{
  struct __timespec64 ts64 = valid_timespec_to_timespec64 (*abstime);

  return __pthread_cond_timedwait64 (cond, mutex, &ts64);
}
#endif /* __TIMESIZE == 64 */
versioned_symbol (libc, ___pthread_cond_timedwait,
                  pthread_cond_timedwait, GLIBC_2_3_2);
libc_hidden_ver (___pthread_cond_timedwait, __pthread_cond_timedwait)
#ifndef SHARED
strong_alias (___pthread_cond_timedwait, __pthread_cond_timedwait)
#endif

if add  #defing GTHREAD_USE_WEAK 0  in libgcc/gthr-posix.h issue is resolved but that is not correct way as it disable weakref for all symbol, please let me know what is correct way to fix this, this i observed with   gcc-9.3.0 gcc and glibc 2.34

Regards
Puneet